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Abstract: The essential oil composition of Lantana camara, Eucalyptus camaldulensis and Eriocephalus africanus was analyzed by means of GC and GC–MS and bioassayed in order to determine their activity against Amaranthus hybridus and Portulaca oleracea. E. camaldulensis essential oil, with spathulenol as the main compound, was the most effective, completely inhibiting germination and seedling growth on both weeds. The essential oil of E. africanus, rich in artemisia ketone, showed activity similar to that of E. camaldulensis on A. hybridus, but it was not so effective against P. oleracea, and L. camara essential oil, with high percentages in sesquiterpene hydrocarbons, also showed higher phytotoxic activity against A. hybridus, inhibiting its germination and seedling length; however, it showed no effect against P. oleracea germination, whereas was effective in significantly reducing its seedling growth at all concentrations assayed. The results suggest the possible use of these essential oils as natural herbicides. [Copyright &y& Elsevier]

Rind oils of nine cultivars of mandarin originated by recent mutation (Loretina, Marisol, Arrufatina, Clemenules, Clemenpons, Hernandina, Oronules, Satsuma Okitsu, Satsuma Owari) belonging to the Citrus reticulata Blanco species and 2 hybrids Fortune (Citrus tangerine Hort. ex Tan x Citrus clementina Hort ex Tan) and Nova (Tangelo Orlando x Citrus clementina Hort ex Tan) were obtained from ripe fruits of trees growing in the same environmental and cultivated conditions. The study of their chemical composition was carried out by capillary GC, GC/MS and the results were submitted to discriminant analysis. The first discriminant function separates the α-thujene chemocultivar, corresponding to oriental mandarin cultivars (Satsuma Okitsu, Satsuma Owari), from the Mediterranean cultivars. Inside this last group, the second discriminant function split up the sabinene chemocultivar (Marisol, Arrufatina Clemenpons and Loretina from the hybrids group (Fortuna and Nova) and alters (Clemenules and Hernandina)). The differential compounds of these groups are: α-thujene α-pinene, sabinene, myrcene, limonene, linalool, α-terpineol and germacrene-D. [Copyright &y& Elsevier]